Well-known · Cross-platform

389 LDAP

TCP Yes
UDP Assigned
SCTP
DCCP

What it is

Lightweight Directory Access Protocol (cleartext / STARTTLS).

When / why

Directory queries and AD authentication. Pair with LDAPS (636); enforce signing in AD.

Protocol status detail

TransportStatusMeaning
TCP Yes Assigned by IANA and standardized, specified, or widely used on this port.
UDP Assigned Assigned by IANA, but not standardized, specified, or widely used on this port.
SCTP Not applicable for this transport.
DCCP Not applicable for this transport.

Port range

Well-known (0–1023). System port for a core service. On Unix-like systems, binding it requires superuser privileges.

Browse all ports →

Firewall rules for port 389

Copy-ready inbound rules for the active transports. Replace every <source> placeholder with the specific host, subnet, or CIDR that should reach this port.

⚠ Unencrypted or unauthenticated by default — prefer a TLS variant or tunnel over VPN/SSH rather than exposing this port directly.

ufw

sudo ufw allow proto tcp from <source> to any port 389

Allow TCP 389 (LDAP). Replace <source> with the network/host that should reach it.

firewalld

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="389" protocol="tcp" accept'

Allow TCP 389 (LDAP) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 389 accept

Allow TCP 389 (LDAP). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 389 -j ACCEPT

Allow TCP 389 (LDAP). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-ldap-389 --priority 1000 --access Allow --direction Inbound --protocol TCP --source-address-prefixes <source> --destination-port-ranges 389

Inbound rule for 389 (LDAP). Set <source> to a CIDR; lower priority number = higher precedence.

AWS Security Group

aws ec2 authorize-security-group-ingress --group-id <sg-id> --ip-permissions IpProtocol=tcp,FromPort=389,ToPort=389,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 389 (LDAP). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-ldap-389 --direction=INGRESS --action=ALLOW --rules=tcp:389 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 389 (LDAP). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow LDAP 389/TCP" dir=in action=allow protocol=TCP localport=389 remoteip=<source>

Inbound TCP 389 (LDAP). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow LDAP 389/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 389 -RemoteAddress <source>

Inbound TCP 389 (LDAP). Replace <source> with a host or subnet.

Rules are generated only for transports marked active for this port. They default to an inbound allow with an explicit source placeholder — never any. Review direction, scope, and rule precedence before applying in production.